In this paper, an attempt is made for the 24-hr prediction of photochemical
pollutant levels using a neural network model. For this purpose, a model i
s developed that relates peak pollutant concentrations to meteorological an
d emission variables and indexes. The analysis is based on measurements of
O-3 and NO2 from the city of Athens. The meteorological variables are selec
ted to cover atmospheric processes that determine the fate of the airborne
pollutants while special care is taken to ensure the availability of the re
quired input data from routine observations or forecasts. The comparison be
tween model predictions and actual observations shows a good agreement. In
addition, a series of sensitivity tests is performed in order to evaluate t
he sensitivity of the model to the uncertainty in meteorological variables,
Model forecasts are generally rather insensitive to small perturbations in
most of the input meteorological data, while they are relatively more sens
itive in changes in wind speed and direction.